Problem: Simplify the following expression: $n = \dfrac{2}{5p} + \dfrac{1}{7p}$
Answer: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $5p$ and $7p$ $\lcm(5p, 7p) = 35p$ $ n = \dfrac{7}{7} \cdot \dfrac{2}{5p} + \dfrac{5}{5} \cdot \dfrac{1}{7p} $ $n = \dfrac{14}{35p} + \dfrac{5}{35p}$ $n = \dfrac{14 +5}{35p}$ $n = \dfrac{19}{35p}$